In this study, local soil samples were collected for the isolation of Streptomyces. Molecular characterization and gene sequencing of 16S rRNA was done for identification of Streptomyces species which has been used in this study as a probiotic in feed. To evaluate their potential and efficacy as a probiotic in-Vivo, day old broiler chicks (total 140) were purchased from local hatchery and acclimatized for seven days and then divided in 07 experimental groups having 20 birds in each entitled as Group A, B, C, D, E, F and G, where group A served as control and all other were supplemented with feed having streptomyces as a supplement (probiotics). Various species of the streptomyces including Streptomyces globiosporus, Streptomyces toxitricin, Streptomyces WSN2, Streptomyces rochie and Streptomyces fimbritus to group B, C, D and E, respectively. Group G was treated with commercially available growth promoter (Greig® BS). Parameters including physiological (feed intake, weight gain, organ weight) and immunological parameters (carbon clearance assay, Lymphoproliferative response to avian tuberculin) of the birds were evaluated, thoroughly. The data thus obtained was subjected to the M-stat C software for statistical analysis. Significant additive effect on the broiler's performance in all treatment groups those received probiotic was observed as compared to the control in terms of physiological and immunological parameters. The birds supplemented with Streptomyces globiosporus revealed the better growth and improved feed intake as compared to all other tested species. Hence, it has been concluded that these local isolates of the streptomyces have potential to be promoted as the probiotic in the poultry feed which will be more economical and profitable to the farmers. [ABSTRACT FROM AUTHOR]